>I would like to drive (4 (or more)) 5x7 dot matrix type LED displays using
>a PIC. All I've ever done before are 7 segment which seem relatively easy
>using latching decoders, etc. I'd like to be able to update the display
>(visually) at least once per second (not a clock but I need to display
>information that could change once every second).

Try the SAA1064 chip, it's a 7 Segment driver with an I2C bus interface.
SAA1064 can drive 4 display which are multiplexed. In addition, there is
possibility to adjust luminosity by simply setting a register (there is
8 value to adjust led current). If you need more than 4 displays, you can
add another SAA1064 on the I2C bus and that's all.

Philippe TECHER wrote:
>
> On Wed, 5 Feb 1997, Scott wrote:
>
> >I would like to drive (4 (or more)) 5x7 dot matrix type LED displays using
> >a PIC. All I've ever done before are 7 segment which seem relatively easy
> >using latching decoders, etc. I'd like to be able to update the display
> >(visually) at least once per second (not a clock but I need to display
> >information that could change once every second).
>
> Try the SAA1064 chip, it's a 7 Segment driver with an I2C bus interface.
> SAA1064 can drive 4 display which are multiplexed. In addition, there is
> possibility to adjust luminosity by simply setting a register (there is
> 8 value to adjust led current). If you need more than 4 displays, you can
> add another SAA1064 on the I2C bus and that's all.
>
> Regards,
> Philippe (.....P.TECHERKILLspam@spam@insat.com)
Try using portb buffered if you need the current as row drivers and
shift out via the a port to N (serial in parallell out) shift registers
also buffered. Tony M.